Excimer Laser-Assisted Recanalization of Long, Chronic Superficial Femoral Artery Occlusions

Tissue post-classification using the measured acoustic signals during 355 nm laser atherectomy procedures

The current laser atherectomy technologies to treat patients with challenging (to-cross) total chronic occlusions with a step-by-step (SBS) approach (without leading guide wire), are lacking real-time signal monitoring of the ablated tissues, and carry the risk for vessel perforation. We present first time post-classification of ablated tissues using acoustic signals recorded by a microphone placed nearby during five atherectomy procedures using 355 nm solid-state Auryon laser device performed with an SBS approach, some with highly severe calcification. Using our machine-learning algorithm, the classification results of these ablation signals recordings from five patients showed 93.7% classification accuracy with arterial vs nonarterial wall material. While still very preliminary and requiring a larger study and thereafter as commercial device, the results of these first acoustic post-classification in SBS cases are very promising. This study implies, as a general statement, that online recording of the acoustic signals using a noncontact microphone, may potentially serve for an online classification of the ablated tissue in SBS cases. This technology could be used to confirm correct positioning in the vasculature, and by this, to potentially further reduce the risk of perforation using 355 nm laser atherectomy in such procedures.

Performance of the Wingman catheter in peripheral artery chronic total occlusions: Short-term results from the international Wing-It trial

OBJECTIVES

To determine the safety and effectiveness of a peripheral artery chronic total occlusion (CTO) crossing catheter following failed crossing attempts with standard guidewires.

BACKGROUND

CTO crossing remains a challenge during peripheral artery interventions.

METHODS

In this prospective, international, single-arm study, patients with a peripheral artery CTO that was uncrossable with standard guidewires were treated with a crossing catheter (Wingman, Reflow Medical). The primary efficacy endpoint of CTO crossing success was compared to a performance goal of 70.7%. The primary composite safety endpoint (major adverse event [MAE], clinically significant perforation or embolization, or grade C or greater dissection) was assessed over a 30-day follow-up period and compared to a performance goal of 13.0%.

RESULTS

A total of 85 patients were treated using the Wingman catheter for peripheral artery CTO crossing. Key patient characteristics were mean age of 71±9 years, 66% male, and mean lesion length of 188±94 mm in the superficial femoral artery (71%), popliteal artery (15%), or infrapopliteal arteries (14%). Both primary endpoints of the trial were met¾CTO crossing success was 90% (lower confidence limit=82.5%) and 5 primary safety events occurred in 4 (4.8%) patients (upper confidence limit=10.7%). Over 30 days of follow-up, Rutherford score decreased by at least 2 categories in 74% patients; the percentage of patients with normal hemodynamics assessed with the ankle-brachial index increased from 1% to 51%.

CONCLUSIONS

Among patients with a CTO that was unable to be crossed with a standard guidewire, the Wingman catheter was able to cross 90% of occlusions with a favorable safety profile.

Excimer laser atherectomy combined with drug-coated balloon angioplasty for the treatment of chronic obstructive femoropopliteal arterial disease

The aim of the present retrospective study was to evaluate the feasibility, safety and the primary results following application of excimer laser atherectomy (ELA) combined with adjunctive drug-coated balloon angioplasty (DCBA) as the first-line endovascular treatment for patients with chronic obstructive femoropopliteal arterial disease. The baseline characteristics and angiographic variables of all patients who underwent ELA for stable chronic obstructive femoropopliteal arterial disease at Tianjin First Central Hospital (Tianjin, China) between May and December 2017 were collected. Information on clinical characteristics, including the 12-month primary patency rate, technical success rate, procedural success rate, bailout stenting rate, target lesion revascularization and major adverse events, was obtained following review of the patients' medical records. A descriptive analysis was performed on all variables. Kaplan-Meier curves were plotted for the primary patency rate. The present study included 17 consecutive patients (age, 68.9±7.4 years; 94.1% males) who were followed up for 12 months after the intervention. Adjunctive BA was performed in 100% of the cases. The occlusion length was 23.3±8.9 cm (range, 5.6–40.5 cm). The technical success rate was 100% and the procedural success rate was 88.2%. Bailout stenting was required in 5 of the 17 patients (29.4%) and the 12-month primary patency rate was 82.4%. The clinically driven target lesion revascularization rate was 5.9% at 12 months. An embolic protection device was used in 23.5% of the patients. The following adverse events were reported: Distal embolization requiring treatment, 5.9% (1 patient with embolic protection device); and flow-limiting dissection requiring treatment, 5.9%. In the present study, there were no major adverse events (all-cause death, unplanned major amputation or target lesion revascularization) at 30 days after the intervention. Therefore, ELA combined with adjunctive DCBA for the treatment of chronic obstructive femoropopliteal arterial disease appears to be safe, practicable and associated with a high procedural success rate; furthermore, endoluminal-driven atherectomy may effectively reduce the requirement for stent placement in the lower limb arteries and is associated with long-term patency.

A quantitative evaluation of the use of medical lasers in German hospitals

The laser has become an integral part of modern medicine, procedures based on this technique have found their way into a multitude of medical disciplines. There is, however, no data available on the detailed quantitative development of laser use in the medical sector. This fact gave rise to the idea of the present study, which analyzed the raw data of the quality report of German hospitals with respect to this subject. Over the 9 years of report, a steady increase in the cumulative number of cases was evident, although not all body regions in which the medical laser is used followed this trend. The CO₂ laser was found to be the most commonly applied laser, even though a large spectrum of different laser types is used. Based on the present study, the importance of the laser for medical purposes can be confirmed.

Treatment of subacute and chronic thrombotic occlusions of lower extremity peripheral arteries with the excimer laser: a feasibility study

BACKGROUND

Thrombus is highly prevalent in patients with recent symptoms (< 6 months) of claudication or limb ischemia due to an occluded culprit lower extremity vessels. Treatment of these thrombotic occlusions is challenging. In this feasibility study, the excimer laser (Spectranetics, Colorado Springs, CO) has been tested for its safety and ability to ablate thrombus in patients with recent arterial occlusions.

METHODS

Angiographic operator assessment and volumetric core lab quantitation of the thrombus were performed at baseline and after excimer laser but prior to definitive treatment of the vessel to evaluate thrombus resolution. Consecutive patients were prospectively enrolled at a single site. Procedural success was defined as achieving a residual stenosis of <30% after final treatment with no intraprocedural complications requiring additional treatment.

RESULTS

20 consecutive patients were enrolled in this study (8 males, mean age 69.5±11.1 years). Based on patients symptom onset, 12 patients were subacute (> 24 h, < 30 days), and 8 chronic (between 1 to 6 months). 15/20 (75%) had restenotic occlusions. Due to the long, occlusive nature of these lesions, only 8 patients had complete intravascular ultrasound images at each time point which allowed volumetric analysis by the core lab. There was no statistical difference in plaque/thrombus volume between baseline (pretreatment) and excimer laser (P=.68). There was however a significant reduction in residual angiographic stenosis post laser alone (100% vs. 66.75%±23.9%, P=.001). Procedural success was 100%. There were no deaths or amputations. Bail out stenting was performed in 10/20 (50%) patients. Embolic filters were used in 15/20 (75%) of patients. Macrodebris>2 mm were seen in 85.7% of filters. There was no in-hospital or 30-day reocclusion of the treated vessel but one patient had a vascular access complication (small AV fistula) conservatively managed. No other serious adverse events were noted.

CONCLUSION

Using the excimer laser appears safe in this small feasibility study of subacute and chronic thrombotic occlusions. Angiographically, there was a significant reduction in percent stenosis with the laser alone. The limited IVUS data did not show a reduction in plaque/thrombus volume but the number of interpretable ultrasounds was small. Further data are needed to address the effectiveness of the laser in treating these thrombotic occlusions and its advantages over balloon angioplasty.

Outback catheter for femoropopliteal occlusions: immediate and long-term results

PURPOSE

To report a retrospective, single-center study that evaluates technical and clinical outcomes from subintimal recanalization of femoropopliteal chronic total occlusions (CTO) facilitated by the Outback re-entry catheter.

METHODS

The Outback catheter was required to complete recanalization of femoropopliteal CTOs (mean lesion length 195 ± 91 mm) in 118 limbs of 113 patients (77 men; mean age 70 ± 10 years). In 80/118 (67.8%) limbs, treatment was performed for claudication and in the remaining 38 (32.2%) for critical limb ischemia (CLI). Technical and procedural success, clinical outcome, and cumulative patency rates in follow-up were evaluated.

RESULTS

Re-entry was accomplished in 108/118 limbs (91.5%) with recanalization completed in 107/118 (90.7%). Of these, only 61/107 (57%) arteries were left with a residual stenosis <30%. Complications included minor bleeding of the target vessel (5/118, 4.2%) and minor hematoma/pseudoaneurysm at the access site (6/118, 5.1%). Acute reocclusion developed in 2/118 cases (1.7%) without major complication. After 12 months, primary patency was 56.7%, assisted primary patency 83.1%, and secondary patency 89.1%. Primary patency was significantly reduced in limbs with residual stenosis. Over a median 15-month follow-up (range 2-32), 4 major and 2 minor amputations were performed in patients with CLI.

CONCLUSION

The Outback catheter is a reliable tool to recanalize challenging chronic femoropopliteal occlusions after failed guidewire re-entry. Restenosis rates are high, which may be due to the severity and extent of disease in these patients, who are particularly challenging.

Endovascular treatment of peripheral vascular disease

Peripheral arterial disease (PAD) affects about 27 million people in North America and Europe, accounting for up to 413,000 hospitalizations per year with 88,000 hospitalizations involving the lower extremities and 28,000 involving embolectomy or thrombectomy of lower limb arteries. Many patients are asymptomatic and, among symptomatic patients, atypical symptoms are more common than classic claudication. Peripheral arterial disease also correlates strongly with risk of major cardiovascular events, and patients with PAD have a high prevalence of coexistent coronary and cerebrovascular disease. Because the prevalence of PAD increases progressively with age, PAD is a growing clinical problem due to the increasingly aged population in the United States and other developed countries. Until recently, vascular surgical procedures were the only alternative to medical therapy in such patients. Today, endovascular practice, percutaneous transluminal angioplasty with or without stenting, is used far more frequently for all types of lower extremity occlusive lesions, reflecting the continuing advances in imaging techniques, angioplasty equipment, and endovascular expertise. The role of endovascular intervention in the treatment of limb-threatening ischemia is also expanding, and its promise of limb salvage and symptom relief with reduced morbidity and mortality makes percutaneous transluminal angioplasty/stenting an attractive alternative to surgery and, as most endovascular interventions are performed on an outpatient basis, hospital costs are cut considerably. In this monograph we discuss current endovascular intervention for treatment of occlusive PAD, aneurysmal arterial disease, and venous occlusive disease.

Endovascular superficial femoral artery treatment: can it be as good as bypass?

Care of the vascular patient has changed drastically during the last decade, with the introduction of endovascular therapies. Medical management and open surgical bypass have been the traditional options for superficial femoral artery (SFA) occlusive disease. Endovascular revascularization of the SFA, however, has been increasingly utilized during the past decade. Results of endovascular interventions for SFA stenoses and/or occlusions have been mixed. In addition, several different techniques have been developed to address similar lesions. This added complexity makes it difficult to compare endovascular therapies to surgical bypass. This review will discuss the difficulties in comparing open and endovascular therapies as well as outcomes of endovascular therapies. Finally, the role of endovascular interventions for SFA lesions in the future will be discussed.

Endovascular infrainguinal revascularization: technical tips for atherectomy device selection and procedural success

The superficial femoral artery (SFA) is the interventionalist's most frequent adversary in infrainguinal revascularization, and we have yet to conquer it. Despite having numerous devices and techniques in our arsenal, we have, in large part, been unable to devise a treatment that yields not only excellent, safe, and reproducible acute outcomes, but also consistently good results at long-term follow-up. Angioplasty and stenting of the SFA has come under severe criticism due to numerous reports of stent fractures, unacceptable restenosis rates, and lack of US Food and Drug Administration-approved specific stents in this location. An alternative to displacement techniques is now being pursued. These include debulking the atheromatous plaque. We review these techniques and also offer helpful tips to achieve maximum success in infrainguinal revascularization.

Recanalization of infrainguinal vessels: silverhawk, laser, and the remote superficial femoral artery endarterectomy

There are multiple endovascular options to achieve percutaneous revascularization of chronic superficial femoral artery (SFA) stenoses and occlusions. Most rely on forceful displacement of plaque via balloon angioplasty, either as a stand-alone therapy or supplemented by cold thermal injury (cryoplasty), microtome assistance (cutting balloon angioplasty), nitinol stent deployment, or expanded polytetrafluoroethylene-lined nitinol stent deployment. Excellent technical success rates are routinely described in the literature. The essential problem associated with these techniques is the predictable compromise of the initial result by neointimal hyperplasia leading to poor long-term results. An alternative to forceful displacement techniques is use of directional atherectomy or excimer laser to debulk the atheromatous lesion, with the addition of low-pressure angioplasty or stent deployment as needed. Currently, directional atherectomy is performed using the Silverhawk Plaque Excision System (FoxHollow, Redwood City, CA), while laser atherectomy is frequently performed with the CLIRpath Excimer Laser (Spectranetics Corp., Colorado Springs, CO). While both techniques can be utilized for de novo atherosclerotic lesions, even eccentric lesions or ostial lesions, proponents of these devices have also shown good short-term results in the treatment of restenoses. Remote SFA endarterectomy with the Aspire stent (Vascular Architects, San Jose, CA) is a hybrid surgical and endovascular technique that is useful for debulking plaque from the SFA with adjunctive stenting of the distal SFA. We present a review of various alternative techniques to forceful balloon dilation used in the recanalization of the SFA with potential pitfalls and complications, along with a review of literature associated with each of these techniques.

Limb Salvage Following Laser-Assisted Angioplasty for Critical Limb Ischemia:Results of the LACI Multicenter Trial

PURPOSE

To evaluate the effectiveness of laser-assisted angioplasty for patients with critical limb ischemia (CLI) who were poor candidates for surgical revascularization.

METHODS

A prospective registry at 14 sites in the US and Germany enrolled 145 patients with 155 critically ischemic limbs; the patients were poor candidates for bypass surgery owing to inadequate target vessel or saphenous vein, prohibitive cardiac disease, or significant comorbidities (ASA class 4). Additional comorbid risk factors included diabetes in 66%, hypertension in 83%, previous stroke in 21%, and myocardial infarction in 23%. Endovascular treatment included guidewire traversal and excimer laser angioplasty followed by balloon angioplasty with optional stenting.

RESULTS

Occlusions were present in 92% of limbs. A mean of 2.7+/-1.4 lesions were treated per limb; the total median treatment length was 11 cm (mean 16.2, range 0.2-123). Stents were implanted in 45% of limbs. Procedural success, defined as <50% residual stenosis in all treated lesions, was seen in 86% of limbs. At 6-month follow-up, limb salvage was achieved in 110 (92%) of 119 surviving patients or 118 (93%) 127 limbs.

CONCLUSION

Excimer laser-assisted angioplasty for CLI offers high technical success and limb salvage rates in patients unfit for traditional surgical revascularization.

The Use of Femoropopliteal Stent-Grafts for Critical Limb Ischemia

Peripheral vascular disease of the femoropopliteal segment is one of the most common anatomic locations leading to patient symptoms. Traditional open surgical bypass has started to be supplanted by a surge in lower risk endovascular procedures. Though midterm results of endovascular therapy have been acceptable, longer term results, especially in long diffuse disease, appear to be less durable than their surgical alternatives. Recently the Viabahn, a percutaneously placed PTFE stent-graft, has been approved for use in the femoropopliteal artery. Though the majority of the data for this stent-graft has been derived from patients with complex (>10 cm length) lesions, most of the patients have been claudicants. The population with critical limb ischemia is at particularly high risk for cardiovascular mortality and may benefit from this less invasive approach. However, stent-graft utilization is more complex and many variables must be evaluated before and during the procedure to allow for optimal procedural outcomes.

Endograft use in the femoral and popliteal arteries

The results of infra-inguinal intervention for atherosclerotic occlusive disease have not changed dramatically in the last 15 years despite the advent of many different designs of uncovered stents. "Plain old balloon angioplasty" remains the treatment of choice for short lesions (<3 cm) with good morphologic characteristics. Stents have improved suboptimal angioplasty results somewhat, but results in longer lesions >5 cm have remained poor in most series. Although there are no endografts currently approved for arterial use by the FDA, expanded polytetraflouroethylene (ePTFE) covered endoprostheses are available and their use in the femoropopliteal arteries can dramatically improve the results of endovascular treatment for longer lesions and allow one to treat vascular ruptures and aneurysms. In this article, we will review the published results for the use of endografts in the femoropopliteal arteries and describe what we believe to be the current indications for their use.

Long-term results of ePTFE stent-graft versus angioplasty in the femoropopliteal artery: single center experience from a prospective, randomized trial

PURPOSE

To describe a single-center experience as part of a U.S. multicenter prospective randomized trial of PTA versus percutaneous transluminal angioplasty (PTA)- and ePTFE (expanded polytetrafluoroethylene)-covered endoprosthesis placement for the treatment of superficial femoral artery (SFA) and proximal popliteal artery stenoses and occlusions.

MATERIALS AND METHODS

Twenty-eight patients with claudication or ischemia were treated by PTA alone (n = 13) or PTA and endoprosthesis placement (n = 15). Baseline characteristics, including exercise ankle/brachial index (ABI), number of patent runoff vessels, Rutherford-Becker ischemia score, and lesion length, were equivalent. Follow-up included postprocedure, objective, noninvasive vascular evaluation and a clinical status scale for a minimum of 24 months.

RESULTS

Technical success was achieved in 15 of 15 patients (100%) in the endoprosthesis group and 12 of 13 patients (92%) in the PTA group. Complications in the endoprosthesis group included clinically significant embolization (n = 1, successfully treated by thrombolysis) and transient thigh pain that required medication in three patients (20%). Clinical improvement was achieved initially in all patients with a significant increase in exercise ABI in both groups (mean increase from baseline was 0.51 with 95% CI: 0.37-0.64 in endoprosthesis patients and 0.39 with 95% CI: 0.31-0.47 in PTA patients; P =.13). At 6-month follow-up with duplex US, 93% of patients (14 of 15) treated with the Hemobahn endoprosthesis (W.L. Gore & Associates, Flagstaff, AZ) remained primarily patent versus 42% of patients (five of 12) treated with PTA alone. At 2 years follow-up, primary patency remained 87% (13 of 15 patients) in the endoprosthesis group versus only 25% (three of 12 patients) in the PTA group (P =.002). Exercise ABI was >0.15 higher than baseline in 93% of patients (14 of 15) treated with endoprosthesis placement versus 54% of patients (seven of 13) treated by PTA alone. Clinical success was maintained in 87% of patients (13 of 15) in the endoprosthesis group versus 46% of patients (six of 13) in the PTA group.

CONCLUSION

This single-center experience with placement of the Hemobahn endoprosthesis (W.L. Gore & Associates) in the SFA demonstrated a statistically significant improvement in both patency and clinical outcome compared with PTA alone.